zones: load wireguard key pairs on Machine.init()

Signed-off-by: Alejandro Mery <amery@jpi.io>

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/burntSushi/toml v0.3.1
 	github.com/mgechev/revive v1.3.2
 	github.com/spf13/cobra v1.7.0
+	golang.org/x/crypto v0.12.0
 	gopkg.in/gcfg.v1 v1.2.3
 )
 

go.sum

@@ -70,6 +70,8 @@ github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+golang.org/x/crypto v0.12.0 h1:tFM/ta59kqch6LlvYnPa0yx5a83cL2nHflFhYKvv9Yk=
+golang.org/x/crypto v0.12.0/go.mod h1:NF0Gs7EO5K4qLn+Ylc+fih8BSTeIjAP05siRnAh98yw=
 golang.org/x/exp v0.0.0-20230713183714-613f0c0eb8a1 h1:MGwJjxBy0HJshjDNfLsYO8xppfqWlA5ZT9OhtUUhTNw=
 golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
 golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=

pkg/wireguard/keys.go

@@ -2,8 +2,11 @@ package wireguard
 
 import (
 	"bytes"
+	"crypto/rand"
 	"encoding/base64"
 	"errors"
+
+	"golang.org/x/crypto/curve25519"
 )
 
 const (
@@ -16,6 +19,10 @@ const (
 var (
 	// ErrInvalidKeySize indicates the key size is wrong
 	ErrInvalidKeySize = errors.New("invalid key size")
+	// ErrInvalidPrivateKey indicates the private key is invalid
+	ErrInvalidPrivateKey = errors.New("invalid private key")
+	// ErrInvalidPublicKey indicates the public key is invalid
+	ErrInvalidPublicKey = errors.New("invalid public key")
 )
 
 type (
@@ -89,8 +96,77 @@ func decodeKey(data string, size int) ([]byte, error) {
 	}
 }
 
+// NewPrivateKey creates a new PrivateKey
+func NewPrivateKey() (PrivateKey, error) {
+	var s [PrivateKeySize]byte
+
+	_, err := rand.Read(s[:])
+	if err != nil {
+		return []byte{}, err
+	}
+
+	// apply same clamping as wireguard-go/device/noise-helpers.go
+	s[0] &= 0xf8
+	s[31] = (s[31] & 0x7f) | 0x40
+
+	return s[:], nil
+}
+
+// Public generates the corresponding PublicKey
+func (key PrivateKey) Public() PublicKey {
+	if len(key) != PrivateKeySize {
+		return []byte{}
+	}
+
+	out := [PublicKeySize]byte{}
+	in := (*[PrivateKeySize]byte)(key)
+
+	curve25519.ScalarBaseMult(&out, in)
+	return out[:]
+}
+
 // KeyPair holds a Key pair
 type KeyPair struct {
 	PrivateKey PrivateKey
 	PublicKey  PublicKey
 }
+
+// Validate checks the PublicKey matches the PrivateKey,
+// and sets the PublicKey if missing
+func (kp *KeyPair) Validate() error {
+	keyLen := len(kp.PrivateKey)
+	pubLen := len(kp.PublicKey)
+
+	switch {
+	case keyLen != PrivateKeySize:
+		// bad private key
+		return ErrInvalidPrivateKey
+	case pubLen == 0:
+		// no public key, set it
+		kp.PublicKey = kp.PrivateKey.Public()
+		return nil
+	case pubLen != PublicKeySize:
+		// bad public key
+		return ErrInvalidPublicKey
+	case !kp.PrivateKey.Public().Equal(kp.PublicKey):
+		// wrong public key
+		return ErrInvalidPublicKey
+	default:
+		// correct public key
+		return nil
+	}
+}
+
+// NewKeyPair creates a new KeyPair for Wireguard
+func NewKeyPair() (*KeyPair, error) {
+	key, err := NewPrivateKey()
+	if err != nil {
+		return nil, err
+	}
+
+	out := &KeyPair{
+		PrivateKey: key,
+		PublicKey:  key.Public(),
+	}
+	return out, nil
+}

pkg/zones/machine_rings.go

@@ -10,6 +10,77 @@ import (
 	"git.jpi.io/amery/jpictl/pkg/wireguard"
 )
 
+// GetWireguardKeys reads a wgN.key/wgN.pub files
+func (m *Machine) GetWireguardKeys(ring int) (*wireguard.KeyPair, error) {
+	var (
+		data []byte
+		err  error
+		key  wireguard.PrivateKey
+		pub  wireguard.PublicKey
+	)
+
+	data, err = m.ReadFile("wg%v.key", ring)
+	if err != nil {
+		// failed to read
+		return nil, err
+	}
+
+	key, err = wireguard.PrivateKeyFromBase64(string(data))
+	if err != nil {
+		// bad key
+		err = core.Wrapf(err, "wg%v.key", ring)
+		return nil, err
+	}
+
+	data, err = m.ReadFile("wg%v.pub", ring)
+	switch {
+	case os.IsNotExist(err):
+		// no wgN.pub is fine
+	case err != nil:
+		// failed to read
+		return nil, err
+	default:
+		// good read
+		pub, err = wireguard.PublicKeyFromBase64(string(data))
+		if err != nil {
+			// bad key
+			err = core.Wrapf(err, "wg%v.pub", ring)
+			return nil, err
+		}
+	}
+
+	kp := &wireguard.KeyPair{
+		PrivateKey: key,
+		PublicKey:  pub,
+	}
+
+	if err = kp.Validate(); err != nil {
+		return nil, err
+	}
+
+	return kp, nil
+}
+
+func (m *Machine) tryReadWireguardKeys(ring int) error {
+	kp, err := m.GetWireguardKeys(ring)
+	switch {
+	case os.IsNotExist(err):
+		// ignore
+		return nil
+	case err != nil:
+		// something went wrong
+		return err
+	default:
+		// import keys
+		ri := &RingInfo{
+			Ring: ring,
+			Keys: kp,
+		}
+
+		return m.applyRingInfo(ring, ri)
+	}
+}
+
 // GetWireguardConfig reads a wgN.conf file
 func (m *Machine) GetWireguardConfig(ring int) (*wireguard.Config, error) {
 	data, err := m.ReadFile("wg%v.conf", ring)

pkg/zones/machine_scan.go

@@ -25,6 +25,15 @@ func (m *Machine) updatePublicAddresses() error {
 	return nil
 }
 
+func (m *Machine) init() error {
+	for i := 0; i < RingsCount; i++ {
+		if err := m.tryReadWireguardKeys(i); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (m *Machine) scan() error {
 	for i := 0; i < RingsCount; i++ {
 		if err := m.tryApplyWireguardConfig(i); err != nil {

pkg/zones/rings.go

@@ -31,9 +31,9 @@ func (ri *RingInfo) Merge(alter *RingInfo) error {
 	case ri.Ring != alter.Ring:
 		// different ring
 		return fmt.Errorf("invalid %s: %v ≠ %v", "ring", ri.Ring, alter.Ring)
-	case ri.Enabled != alter.Enabled:
-		// different state
-		return fmt.Errorf("invalid %s: %v ≠ %v", "enabled", ri.Enabled, alter.Enabled)
+	case ri.Enabled && !alter.Enabled:
+		// can't disable via Merge
+		return fmt.Errorf("invalid %s: %v → %v", "enabled", ri.Enabled, alter.Enabled)
 	case !canMergeAddress(ri.Address, alter.Address):
 		// different address
 		return fmt.Errorf("invalid %s: %v ≠ %v", "address", ri.Address, alter.Address)
@@ -42,6 +42,15 @@ func (ri *RingInfo) Merge(alter *RingInfo) error {
 		return fmt.Errorf("invalid %s: %s ≠ %s", "keys", ri.Keys, alter.Keys)
 	}
 
+	return ri.unsafeMerge(alter)
+}
+
+func (ri *RingInfo) unsafeMerge(alter *RingInfo) error {
+	// enable via Merge
+	if alter.Enabled {
+		ri.Enabled = true
+	}
+
 	switch {
 	case ri.Keys == nil:
 		// assign keypair

pkg/zones/scan.go

@@ -129,6 +129,10 @@ func (z *Zone) scan() error {
 				Name: e.Name(),
 			}
 
+			if err := m.init(); err != nil {
+				return err
+			}
+
 			z.Machines = append(z.Machines, m)
 		}
 	}